ELK Stack Upgrade from RHEL 7 to RHEL 8 for a Global Investment Company




Client
The client is one of the world’s largest global investment management firms, offering a range of retirement services, advisory solutions, and financial insights to millions of individuals and institutions.
Project Context
Their production ELK environment (10 Elasticsearch, 2 Kibana, 2 Fleet, and 2 Logstash nodes) ran on RHEL 7. They needed an OS upgrade and explored Amazon Linux but decided on RHEL 8 for operational consistency.

Project Objectives
- Upgrade ELK across production and DR clusters
- Evaluate Amazon Linux as an alternate OS
- Improve shard usage, alerting, and cluster health

Challenges
- Coordination of rolling upgrades across tiers
- Managing DR-first migration and resumption of CCR
- Heterogeneous OS complexity
Solution
- Tiered node upgrades (hot → cold → warm → frozen)
- Resolved shard allocation, LDAP, and alerting issues
- Provided licensing cost recommendations and sizing analysis
Testimonial
With zero downtime and future-focused configs, this was the ideal upgrade.



